Well casing cutter and sealer

ABSTRACT

Apparatus for rapidly terminating flow through a well upon sensing of an unsafe well condition. A housing surrounds the well casing and defines a chamber within which a blade is located with its cutting edge adjacent the well casing. An explosive charge positioned against the blade is electrically connected to sensors in the area of the well outlet. When a sensor detects an unsafe condition, the explosive charge is initiated, driving the blade through the well casing without crushing of the casing. When the unsafe condition is corrected, a plug is withdrawn, permitting retraction of the blade and replacement of the explosive charge, thus making the apparatus ready for reuse.

United States Patent 1 Petrick Oct. 23, 1973 1 WELL CASING CUTTER ANDSEALER [76] Inventor: John T. Petrick, 21 Ridgemore Cir.,

Fredericksburg, Va. 22401 [22] Filed: Apr. 20, 1972 [21] Appl. No.:245,728

[52] U.S. Cl 166/55, 166/63, 166/72 [51] Int. Cl E2lb 29/02 [58] Fieldof Search 166/297, 53, 55,

[56] References Cited UNITED STATES PATENTS 1,851,894 3/1932 Clough166/55 1,875,673 9/1932 Stockstill. 166/55 1,949,672 3/1934 Barrier166/55 3,419,076 12/1968 Sizer et al. 166/72 X 3,603,387 9/1971Schoefflerf... 166/55 3,620,299 11/1971 Wiseman 166/53 X 3,631,9281/1972 Dalzell l66/55.l X 3,662,824 5/1972 Page 166/72 8/1972 Garrett166/55 9/1972 Brown 166/55 Primary ExaminerDavid H. Brown Attorney-JohnW. Behringer et a1.

[57] ABSTRACT Apparatus for rapidly terminating flow through a well uponsensing of an unsafe well condition. A housing surrounds the well casingand defines a chamber within which a blade is located with its cuttingedge adjacent the well casing. An explosive charge positioned againstthe blade is electrically connected to sensors in the area of the welloutlet. When a sensor detects an unsafe condition, the explosive chargeis initiated, driving the blade through the well casing without crushingof the casing. When the unsafe condition is corrected, a plug iswithdrawn, permitting retraction of the blade and replacement of theexplosive charge, thus making the apparatus ready for reuse.

9 Claims, 6 Drawing Figures PAIENTEBMT 2 I978 SHEET 10F 2 FIG] WELLCASING CUTTER AND SEALER The present invention pertains to a wellsealer. More particularly, the present invention pertains to appara tusfor automatically and rapidly sealing a well to cut off flow therefromin the event of a blow-out, fire or other hazardous condition.

There have been numerous costly disasters involving fires on oil wells.Many of these have been on landbased wells. Other diasters have been onwells on sea platforms, pumping petroleum from beneath the sea bed.Ordinarily, a well pumping petroleum products operates in a safe andefficient manner with no damage to people or equipment in the area. Alltoo often, however, accidents occur which result in oil'from the wellbeing lost. Frequently, such accidents involve fire, since the oil ishighly combustible. Continued'emission of oil from a well provides acontinuous source of fuel for a tire. Consequently, when a fire occurson a well, it generally is of major proportions, involving considerableloss, both loss of life and monetary loss. Putting out anoil well fireis an extremely difficult, hazardous and time-consuming thing.I-Ieretofore, it generally has involved attempting to cap the well atits outlet. This is very difficult with a land based well. It is evenmore difficult with a well based on a sea platform. In addition, a wellbased on a sea platform presents the further hazard of there being 'noplace for people to escape, since the platform is of limited area and issurrounded by water, for example an ocean, and since the fire frequentlyconsumes the entire platform. Oil well platforms usually have severalwells operating simultaneously, any one of which could cause a tire thatwould then involve all of the wells and the entire platform. Adisastrous fire can end production from the site.

There have been developed, devices for terminating the flow of oilthrough a well. US. Pat. Nos. 3,272,222, 3,416,767, and 3,561,526illustrate typical known apparatus. Such apparatus frequently operate bycrushing the well casing and tubing to block flow therethrough. Oncesuch apparatus has been used, the well casing and tubing must bereplaced, since they have been crushed. This, of course, is an expensiveand time-consuming task. In addition, the apparatus must be installed atthe time the well is initially installed. Consequently, that apparatuscannot be utilized with existing wells. Since the apparatus ishydraulically or hand-operated, an appreciable time delay exists betweenthe detection of the need for terminating the oil flow and the operationof the device to terminate the oil flow.

The present invention is an apparatus for sensing the need to terminateflow from a well and to terminate that flow automatically and rapidlyand yet in a manner which readily permits the flow to be resumed. Wellssometimes include an outer pipe, referred to as the well casing, and aninner pipe,- referred to as a well tubing. Other times, only a singlepipe is provided in a well. In the following specification and claims,the pipes of both of these types of wells are referred to as well pipe.In accordance with the present invention, a well pipe has a housingplaced around it over a portion ofits length, with a bladepositionedwithin the housing and adjacent the well pipe. An explosive charge in aposition to actuate the blade is connected to sensors in the area ofthewell outlet. If a sensor detects a condition which makes it desirable torapidly terminate flow from the well, the explosive charge is initiated,driving the blade through the well pipe to terminate flow from the well.The sharp blade and the rapid, high powered energy, resulting from theexplosive charge,'result in the pipe being severed with little or nocrushing. With flow from the well terminated, the undesirable conditioncan be corrected. Once the condition has been corrected, the blade iswithdrawn, permitting flow to resume. A new explosive charge can then beinstalled, making the apparatus ready for reuse.

These and other aspects and advantages of the present invention are moreapparent in the following detailed description and claims, particularlywhen considered in conjunction with the accompanying drawings in whichlike parts bear like reference numerals. In the drawings:

FIG. I is a schematic illustration of a well based on a sea platform andincorporating flow-terminating apparatus in accordance with the presentinvention;

FIG. 2 is a sectional view of flow-terminating apparatus in accordancewith the present invention ready for actuation;

FIG. 3 is a sectional view of the apparatus of FIG. 2 but afteractuation and in a position preventing flow through a well pipe;

FIG. 4 is a sectional view of the apparatus of FIG. 2 after actuationand returned to its initial position ready for reuse;

FIG. 5 is a sectional view of a modified embodiment of flow-terminatingapparatus in accordanc with the present invention; and

FIG. 6 is a schematic illustration of flow-terminating apparatus inaccordance with the present invention installed for use on a land-basedwell.

FIG. 1 illustrates an oil well 10 based on a sea platform 12. Platform12 includes upper surface 14 and a plurality of support members 16extending downwardly from surface 14 into the sea water 19. Each supportmember 16 has a stabilizing member 18 at its lower end. Well pipe 20extends from beneath the sea bed 22 through upper surface 14 toequipment 24 which controls the pumping, storage and shipment of oilfrom an area beneath sea bed 22 through well pipe 20. This much of thesea-based oil well 10 is conventional, known equipment.

Housing 26 encircles pipe 20 over a portion of its length at a depthbeneath the surface of the sea. As illustrated in FIG. 1, housing 26preferably is made up of a smaller portion 25 and a larger portion 27which are .placed about pipe 20. After housing portions 25 and- 27 arein place, the two portions are secured together by means such as bolts28.

.As seen in FIG. 2, within portion 27 of housing 26 is chamber 31 withinwhich is blade 32. The sharpened tip 34 of blade 32 is adjacent pipe 20,and plug 36 seals the opposite end of portion 27. By way ofillustration, plug 36 can threadedly engage housing portion 27. Recess38 is formed on the inner surface of plug 36 and contains an explosivecharge 40. Wires 42 pass from charge 40 to sensors 58 on upper platform14. A threaded recess 44 is provided in the surface of blade 32 adjacentplug 36.

and to sensors 58 on upper surface 14 of platform 12.

As illustrated, a plurality of sensors 58 can be provided at variouslocations on surface 14 to ensure rapid detection of hazards at thesevarious locations. If desired, additional sensors 58 can be positionedbeneath surface 14, for example on stabilizing members 18 or on pipe 20.The sensors 58 might be adapted to detect such unsafe conditions asfire, smoke, high tempera- 74. Thus, if one or more of the sensors 58detects an unsafe condition, the apparatus is actuated to terminate flowof oil from well 70. A small shaft 76 extends from the earths surface toa point permitting removal of plug 36 for retraction of blade 32 andreplacement of explosive charge 40.

While the above description has been with reference to an oil well, theapparatus of the present invention is equally suited for use in rapidlysensing unsafe conditions and terminating flow from other types ofwells. Although the present invention has been described with referenceto preferred embodiments, numerous tures, escape of oil or 'acombination of such condito be applied via lines42 to initiate explosivecharge 40. As a consequence, a high thrust is applied to blade 32,driving the blade rapidly through well pipe 2 0, without crushing thepipe; Blade 32 blocks passage of' oil through pipe 20,-terminating flowfrom well 10. Anvil 46 prevents blade 32 from rupturing housing portion25. Sealing rings 48, 50, and 52 prevent escape of oil from withinhousing 26. Once blade 32 has reached the position of FIG. 3, additionalgases resulting from initiation of explosive charge 40 escape throughorifice 56.

When the unsafe condition which has caused actuation of the apparatushas been corrected, plug 36 is removed, for example by a diver. Athreaded tool is then insertedvto engage threaded opening 44, and blade32 is retracted. A new explosive charge 60 is inserted intoto reduce thevolume of recess 3.8 into which explosive. c'harge'60 is spaced. Withplug 36 replaced and explosive charge 60 in place and connected tosensors 58, the apparatus is ready for reuse.

FIG. 5 illustrates a modified embodiment of apparatus in accordance withthe present invention. An opening 64 is provided through the wall ofhousing 26 and is closed by plug 66. A similar opening 68 passes throughblade 32 at an angle from a side of blade 32 to the lower surface ofblade 32. Openings 64 and 68 are positioned so that opening 68 isaligned with opening 64 after the device has been actuated to move-blade32 to its position across pipe 20. If blade 32 is not a sufficient sealto terminate flow from the well, plug 66 is removed, and a sealant isintroduced through openings 64 and 66, thereby assuring termination offlow.

FIG. 6 depicts a land-based well 70, including well pipe 72 whichp'assesfrom the earth's surface to a petroleum bed beneath the earths surface.Equipment 74 is provided to pump oil from that petroleum bed to suitablereceiving means. Housing 26 encircles pipe 72 over a portion of itslength and has its wires 42 connected to sensors 58 at suitablelocations on equipment modifications and rearrangements could be madeand still the result would come within the scope of the invention. Q

What is claimed is: V

1. Apparatus for rapidly terminating flow from a well upon sensing of anunsafe well condition comprising:

a housing adapted to encircle a well pipe over a portion of the lengththereof'to define a chamber;

a blade within the chamber adapted for positioning withth'e bladecutting edge adjacent the wall pipe, the blade having a threaded recessin an end opposite the blade cutting edge;

means defining a recess within said housing, adjacent said bladethreaded recess, and adapted to hold an explosive charge;

a plug threadedly mating with said housing recess,

' 'whereby, upon removal of said plug from said housing recess, athreaded tool can be threadedly inserted into the blade threaded recessto permit retraction of said blade; and

circuit means connected to the housing recess and adapted for connectionto sensing means for initiatingan explosive charge within the housingrecess in response to sensing of an unsafe well condition to drive saidblade through the well pipe, terminating flow therethrough.

2. Apparatus as claimed in claim 1 in which said housing comprises afirst housing portion, a second housing portion, and means for joiningsaid first and second housing portions about a well pipe.

3. Apparatus as claimed in claim 1 further comprising sensing meansconnected to said circuit means for sensing unsafe wellconditions.

4. Apparatus as claimed in claim 3 further comprising an explosivecharge within said housing recess.

5. Apparatus for rapidly terminating flow from a well upon sensing of anunsafe well condition comprising:

a housing adapted to encircle a well pipe over a portion of the lengththereof to define a chamber;

a blade within the chamber adapted for positioning with the bladecutting edge adjacent the well pipe; means defining a recess adjacentsaid blade and adapted to hold an explosive charge; and

circuit means connected to the recess and adapted a flow-terminatingposition, for passage of a sealant through the openings.

6. Apparatus as claimed in claim 5, in which said housing comprises afirst housing portion, a second housing portion, and means for joiningsaid first and second housing portions about a well pipe.

7. Apparatus for rapidly terminating flow from a well upon sensing of anunsafe well condition comprising:

a housing adapted to encircle a well pipe over a portion of the lengththereof to define a chamber;

a blade within the chamber adapted for positioning with the bladecutting edge adjacent the well pipe;

means defining a recess adjacent said blade and adapted to hold anexplosive charge;

said housing having an opening thereinto at a point intermediate theblade cutting edge and said defining means;

sealing means intermediate the opening and the blade cutting edge forpreventing leakage from a well pipe out the opening; and circuit meansconnected to the recess and adapted for connection to sensing means forinitiating an explosive charge within the recess in response to secondhousing portions about a well pipe.

1. Apparatus for rapidly terminating flow from a well upon sensing of anunsafe well condition comprising: a housing adapted to encircle a wellpipe over a portion of the length thereof to define a chamber; a bladewithin the chamber adapted for positioning with the blade cutting edgeadjacent the wall pipe, the blade having a threaded recess in an endopposite the blade cutting edge; means defining a recess within saidhousing, adjacent said blade threaded recess, and adapted to hold anexplosive charge; a plug threadedly mating with said housing recess,whereby, upon removal of said plug from said housing recess, a threadedtool can be threadedly inserted into the blade threaded recess to permitretraction of said blade; and circuit means connected to the housingrecess and adapted for connection to sensing means for initiating anexplosive charge within the housing recess in response to sensing of anunsafe well condition to drive said blade through the well pipe,terminating flow therethrough.
 2. Apparatus as claimed in claim 1 inwhich said housing comprises a first housing portion, a second housingportion, and means for joining said first and second housing portionsabout a well pipe.
 3. Apparatus as claimed in claim 1 further comprisingsensing means connected to said circuit means for sensing unsafe wellconditions.
 4. Apparatus as claimed in claim 3 further comprising anexplosive charge within said housing recess.
 5. Apparatus for rapidlyterminating flow from a well upon sensing of an unsafe well conditioncomprising: a housing adapted to encircle a well pipe over a portion ofthe length thereof to define a chamber; a blade within the chamberadapted for positioning with the blade cutting edge adjacent the wellpipe; means defining a recess adjacent said blade and adapted to hold anexplosive charge; and circuit means connected to the recess and adaptedfor connection to sensing means for initiating an explosive chargewithin the recess in response to sensing of an unsafe well condition todrive said blade through the well pipe, terminating flow therethrough;said housing having an opening through a wall thereof and said bladehaving an opening therethrough, said blade opening aligned with saidhousing opening when said blade is across a well pipe in aflow-terminating position, for passage of a sealant through theopenings.
 6. Apparatus as claimed in claim 5, in which said housingcomprises a first housing portion, a second housing portion, and meansfor joining said first and second housing portions about a well pipe. 7.Apparatus for rapidly terminating flow from a well upon sensing of anunsafe well condition comprising: a housing adapted to encircle a wellpipe over a portion of the length thereof to define a chamber; a bladewithin the chamber adapted for positioning with the blade cutting edgeadjacent the well pipe; means defining a recess adjacent said blade andadapted to hold an explosive charge; said housing having an openingthereinto at a point intermediate the blade cutting edge and saiddefining means; sealing means intermediate the opening and the bladecutting edge for preventing leakage from a well pipe out the opening;and circuit means connected to the recess and adapted for connection tosensing means for initiating an explosiVe charge within the recess inresponse to sensing of an unsafe well condition to drive said bladethrough the well pipe, terminating flow therethrough.
 8. Apparatus asclaimed in claim 7 further comprising additional sealing means adaptedto encircle a well pipe on opposite sides of the chamber for preventingleakage from a well pipe out of said apparatus.
 9. Apparatus as claimedin claim 7, in which said housing comprises a first housing portion, asecond housing portion, and means for joining said first and secondhousing portions about a well pipe.